Gewisse Segalsche Algebren auf lokalkompakten Gruppen

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On the Spectroscopic and Thermochemical Properties of ClO,BrO, IO,and Their Anions

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.     

Proximity-Effect-Induced Superconductivity in Nb/Sb2Te3-Nanoribbon/Nb Junctions

Nanohybrid superconducting junctions using antimony telluride (Sb₂Te₃) topological insulator nanoribbons and Nb superconducting electrodes are fabricated using electron beam lithography and magnetron sputtering. The effects of bias current, temperature, and magnetic field on the transport properties of the junctions in a four-terminal measurement configuration are investigated. Two features are observed. First, the formation of a Josephson weak-link junction. The junction is formed by proximity-induced areas in the nanoribbon right underneath the inner Nb electrodes which are connected by the few tens of nanometers short Sb₂Te₃ bridge. At 0.5 K a critical current of 0.15 µA is observed. The decrease of the supercurrent with temperature is explained in the framework of a diffusive junction. Furthermore, the Josephson supercurrent is found to decrease monotonously with the magnetic field indicating that the structure is in the small-junction limit. As a second feature, a transition is also observed in the differential resistance at larger bias currents and larger magnetic fields, which is attributed to the suppression of the proximity-induced superconductive state in the nanoribbon area underneath the Nb electrodes.     

Über das Synthese-Problem für nilpotente Liesche Gruppen

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The physical state space of quantum electrodynamics

Starting from the fact that electrically charged particles are massive, we derive a criterion which characterizes the state space of quantum electrodynamics. This criterion clarifies the special role of the electric charge amongst the uncountably many superselection rules in quantum electrodynamics and provides a basis for a general analysis of the infrared problem. Within this framework we establish the existence of asymptotic electromagnetic fields in all charge-sectors, find a general characterization of infra-particles and introduce a notion of asymptotic completeness.     

Theory of molecular collective excitation in the scattering of identical nuclei

The excitation of nuclear molecules, formed in the scattering of ¹²C on ¹²C, is treated by the collective two-center model (CTCM). The model is referred to a rotating coordinate system and describes the continuous transition from the collective states of the separated nuclei to the states of the compound system. The diagonalization of the interaction between the nuclei leads to a splitting of the excitation energies as function of parity and angular momentum projection. The theory is applied for the explanation of the molecular resonances observed in the ¹²C-¹²C scattering.     

Analysis of stem cell lipids by offline HPTLC-MALDI-TOF MS

MALDI-TOF MS is traditionally used for “proteomics”, but is also a useful tool for lipid analysis. Depending on the applied matrix, however, some lipid classes are more sensitively detected than other ones and this may even lead to suppression effects if complex mixtures are analyzed. Therefore, a previous separation into the individual lipid classes is necessary. Using artificial lipid mixtures or easily available tissue extracts, it has been already shown that HPTLC-(High Performance Thin-Layer Chromatography)-separated lipids can be conveniently analyzed by MALDI-TOF MS directly on the TLC plate. Here we present an initial TLC-MALDI study of the lipid composition of ovine mesenchymal stem cells. Due to the complex composition of these cells, data are also compared to lipids extracted from human erythrocytes. It will be shown that even very minor lipid classes can be easily detected and with much higher sensitivity than by common staining protocols. Additionally, MS images of the developed TLC plates will be shown and potential applications, new methods of data analysis as well as problems discussed.

Chip‐based electrochromatography coupled to ESI‐MS detection

In this study, we present the coupling of chip‐based electrochromatography to MS using a glass chip with a monolithically integrated nanoelectrospray emitter. As separation column, an acrylate‐based porous polymer monolith is implemented into the glass chip by photopolymerization. For the establishment and development of this method, we used a test mixture detectable with both fluorescence and ESI‐MS. After successful evaluation of the approach with the test solutes, it was applied exemplarily for drug analysis such as high‐speed separations of benzodiazepines in pharmaceuticals.